Kslgetl (ksl-get-l-latch) is the function call for to get a latch. Kslwt is function call to get wait interface.

13-July
When you update a table with Zone Maps – that specific zone will be get invalidated and rest of the zone maps will be usable by CBO. So, the Zone map can be completely or partially STALE.

10-July
ZONE Maps: is like EXADATA Storage Index structure, but physically existing in the data dictionary, while storage Indexes are populated to the memory at the run time automatically. ZONE maps need to be created and capture the MAX and MIN values (aggregated values) for a 8MB of a table. During rune time, Oracle inspects this information to decide whether a physical read is required or not for a specific zones.

SQL&gt; create materialized zonemap employee_sex_zm on employee(sex);

Unlike indexes, Zone maps will not be updated automatically during a DML operation. If is behave more like Materialized views – Its on DEMAND.

IMCO Process: Oracle IMCO process is responsible for population or re-population of column stores for in-memory enabled objects set as LOW/MEDIUM/HIGH/CRITICAL. IMCO process populate the column store starting from the table where the priority is set to CRITICAL, then continue in the order HIGH, MEDIUL and LOW. The tables where priority is set to NONE will not be populated by IMCO process. No more tables will be populated once the allocated memory (INMEMORY_SIZE) is full.

Procedure detach the DEFAULT_MAINTENANCE_PLAN from the Scheduler Windows. First identify the maintenance windows attached to the

inmemory_clause_default
inmemory_force
inmemory_max_populate_servers
inmemory_query
inmemory_size – Size of the im-memory column store. Default is 0 and minimum should be 100M. This parameter can be set in PDB level and control the usage, if not set explicitly, will inherit from the CDB. However, CDB value is the total amount of memory available for all PDBs. SGA_TARGET or MEMORY_TARGET considered when we are changing the INMEMORY_SIZE as it is part of the SGA. The inmemory heap divides into two components – IMCA_RW and IMCA_RO – one compartment got the column store (80%) while the other got journal and other related memory structures (20%).

Where in row:479.479 => <total number of index entries>: <Number of Non-deleted index entries>
In older versions row:nrow:rrow
Where nrow => Number of index entries
rrow => Number of non-deleted index entries
avs => is the free space available in the block bytes

02-July
Oracle Big Data SQL: is a unified query mechanism to address various types of data source – a relation database, HDFS or any NoSQL data source. Oracle Big Data SQL deploys a mechanism known as Query Franchising to access the data from various data sources alternate to the Language federation. These are the light weight dedicated agents deployed in each data source to mine the data. These agents are capable to do smart scan functions and return the desired result sets.
For example during the query parsing time, the oracle databases interrogated the HDFS Name Node to locate the Hadoop Data Locations (or InputSplits) . From this information the data access method is delveloped and sends to the Big data agents working in the storage cells or data nodes. Read more details at:http://www.oracle.com/technetwork/database/bigdata-appliance/learnmore/bigdatasqloverview21jan2015-2408000.pdf?ssSourceSiteId=ocomen